A pair of rear frames which extends substantially in the longitudinal direction of a vehicle body is provided at the left and right sides of the rear portion of a vehicle. The rear frames are fixed to a rear panel which forms a rear wall of the vehicle body at the rear end thereof, and are fixed to side sills which are provided on both sides of the vehicle body at the front end thereof. The rear frames transmit the collision load to the left and right side sills and absorb the collision energy by collapsing along substantially the longitudinal direction thereof during the rear-end collision. The rear frames are fixed to each other using a cross member at the front ends and substantially the middle positions thereof. Furthermore, the rear frames are fixed to a spare tire pan where a spare tire is stored (for example, refer to Japanese Unexamined Patent Application, First Publication No. 2004-338419).